Inboard outboard drive

ABSTRACT

A stern drive for a boat having an inboard engine and an outboard drive unit wherein the inboard drive shaft is connected to the propeller shaft by a two section power transmission shaft, the first section being connected to the engine drive shaft at one end by a first universal joint and connected to the second section by a second universal joint. The second section of the power transmission shaft inclines downwardly and rearwardly and is connected to the propeller shaft at an acute angle by two pair of bevel gears. The drive unit is supported for universal pivoting movement about the axis of the first universal joint. A steering mechanism and a shock-absorbing unit are enclosed within the casing for the drive unit.

g an inboard enthe inboard drive by a two section eing connected to I United States Patent [111 5 lnventor Aldo Celli 3,136,285 6/1964 Kiekhaefer 601 Fisher Bldg, Detroit, Mich. 48202 3,382,838 5/1968 Bergstedt Appl. No. 846,024 3,399,647 9/1968 Alexandenh. et al....... July 1969 Primary Examiner-Milt0n Buchler Assistant Examiner-Carl A. Rutledge Arlorne v-Barnes, Kisselle, Raisch & Choate INBOARD OUTBOARD DRIVE 13 Claims, 4 Drawing Figs. ABSTRACT: A stern drive for a boat havm gme and an outboard drive unit wherein 115/35, shaft is connected to the propeller shaft 244/41 power transmission shaft, the first section b the engine drive shaft at one end b d to the second section by a second nd section of the power transmissio rdly and rearwardly and is connected shaft at an acute angle by two pair of bevel unit is supported for universal axis of the first universal joint. A steerin shock-absorbing unit are enclosed within drive unit.

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m S m m m T m u n N n m m E H. m m w m m M m N 6mm m m a m n n CT. I u Ae m m mT m m m a s a m m U 0 n r N5 m m U m u L m n c m L .w .m h F 4 l 1 l n l. 6 H w w m [22] Filed [45] Patented June29, 1971 Hansson et PATENTEU JUN29 [97$ SHEET 1 [1F 2 INVENTOR A100 6544/ 76 M M? M ATTORNEYS PATENIEU JUN29 I97! SHEET E OF 2 INVENTOR FIG. 4

ATTORNEYS INBOARD OUTBOARD DRIVE This invention relates to a stern drive for a boat and particularly to an inboard outboard drive of the type wherein an engine is stationarily mounted inboard of the boat and is connected to a tiltable outboard drive unit.

Inboard outboard drives of the type to which the present invention relates usually incorporate a universal joint which connects the engine drive shaft with an upper set of bevel gears. A vertical shaft driven by the upper set of bevel gears connects with the propeller shaft through a lower set of bevel gears. The universal joint allows the whole drive unit to be pivoted about a vertical axis for steering and about a horizontal axis so as to tilt the drive unit upwardly when it encounters an underwater obstruction or to enable the drive unit to be tilted rearwardly and upwardly out of the water for servicing. The conventional inboard outboard unit of the type described has certain disadvantages from the standpoint of friction losses, noise, size of the submerged portion of the drive unit and cost.

The present invention has for its primary object the provision of an inboard outboard drive which is more economical and more efficient than conventional drives of this type and in which the underwater portion of the drive unit is of minimum size and presents a minimum of drag.

More specifically, it is an object of this invention to provide an inboard outboard drive which includes two successively arranged universal joints-betweenthe engine drive shaft and a downwardly and rearwardly inclined driven shaft and two sets of relatively small bevel gears forming the driving connection between the downwardly inclined shaft and the propeller shaft.

A further object of this invention resides in the provision of an inboard outboard drive unit which includes a casing for the drive unit in which a steering linkage and a shock-absorbing arrangement are substantially completely enclosed.

In the drawings:

FIG. I is a vertical sectional view through the rear end of a boat with the inboard outboard drive arrangement of the present invention mounted thereon.

FIG. 2 is a rear elevational view of the inboard outboard unit with parts broken away.

FIG. 3 is a sectional view along the line 3-3 in FIG. 1.

FIG. 4 is a vertical sectional view through the transom of the boat and showing the manner in which the inboard outboard drive of this invention is resiliently mounted thereon.

Referring to the drawings, there is illustrated in FIG. I the rear end of a boat, the transom of which is designated and the bottom designated 12. Transom 10 is formed with a central circular opening 14 through which the cylindrical flange 16 of an inner'bracket 18 extends. Bracket 18 has a generally flat plate portion 20 which is located slightly inwardly of and generally parallel to the flat inner surface 22 of transom 10. On the outer face 24 of transom 10 there is mounted around opening 14 a generally circular drive unit support bracket 26. As is shown in FIG. 4 brackets 18 and 26 are preferably mounted on transom 10 by means of screws 19 passing through rubber grommets 21 arranged within threaded sleeves 23. Sleeves 23 extend through openings in transom 10 and are secured to the transom by nuts 27 threaded on the inner ends of sleeves 23.

Bracket 26 is provided with a depending support portion 28 formed with a pair of vertically spaced lugs 30 in which a lower pivot pin 32 is fixed. The upper central portion of bracket 26 is formed with a bearing socket 34 in which a pivot pin 36 is journaled as by hearing 38. The axes of pivot pins 32 and 36 are coaxially aligned and lie in a vertical plane. Pivot pins 32, 36 pivotally support a steering bracket 40. Bracket 40 is supported on pin 32 by bearings 42 and is connected to pin 36 by a nut 44 threaded on the end of stud extension 46 on pin 36 whi h extends through a bushing 48 seated in bracket 40.

The casing for the outboard drive is generally designated 50 and is formed with a pair of horizontally extending spindles 52 (FIG. 2) which project into and are pivotally supported within bearing sockets 54 on bracket 40. The horizontal axis of spindles 52 which enable casing 50 to tilt upwardly and downwardly on bracket 40 intersects the axis of pins 32, 36 at the point designated 0. Casing 50 can be tilted upwardly in a counterclockwise direction as viewed in FIG. 1 to a position wherein a ball detent 53 on casing 50 is adapted to interengage with a socket member 55 on bracket 18 to lock or retain the drive unit in an elevated, out of water position. The relative location of detent 53 and socket 55 in the same vertical plane is shown in FIG. 2.

The output or drive shaft of the stationarily mounted inboard motor is designated 56. Shaft 56 extends through the cylindrical'flange 16 of bracket 18 and is supported by a bearing 58 mounted on wall 60 of bracket 18. Shaft 56 has its rear end connected with the outer part 62 of a universal joint generally designated 64. The inner part 66 ofjoint 64 is connected to one end of a downwardly and rearwardly inclined stub shaft 68. Shaft 68 extends through a bearing sleeve 70 fixedly secured to a support flange 711 within casing 50 as by screws 72. The pivot axis of universal joint 64 coincides with the point 0. Stub shaft 68 is journaled in sleeve 70 by bearings 74, 76. The other end of stub shaft 68 is connected to the inner part 78 ofa second universal joint 80. The outer part 82 of joint is connected to a second downwardly and rear wardly inclined stub shaft 84 which is journaled as by bearings 86 is a cap 88 fixedly secured within casing 50 by screws 90. The lower end of shaft 84 is externally splined as at 92 and is interengaged with the internally splined upper end 94 of a tubular shaft 96. The lower end of tubular shaft 96 is supported in the lower end portion of casing 50 by radial bearing 98 and thrust bearing 100. The intermediate portion of tubular shaft 96 is supported by radial bearing 102.

It will be observed that casing 50 comprises an upper portion 104 and a lower portion 106 which are secured together by screws 108. Bearings 98, and 102 are mounted in a rigid support portion 110 formed integrally with the lower portion 106 of casing 50. The flat rearwardly extending surface 112 of the lower casing portion 106 forms an anticavitation plate which is located directly above propeller 114. Propeller 114 is mounted on a propeller shaft 116 journaled on the lower casing portion 106 as by bearings 118 and 120.

A second tubular shaft 122 is journaled in the rigid support portion 110 by bearings 124, 126 and 128. Shaft 122 is parallel to tubular shaft 96 and each of these shafts intersects the axis of propeller shaft 116 at a fixed angle of about 60. Shaft 96 is formed around its outer periphery with a gear 130 and shaft 122 is likewise formed around its outer periphery with a gear 132. Spur gears 130 and 132 are interconnected by an idler gear 134 (FIG. 3) journaled in the rigid support portion 110 on a stub shaft 136. Shaft 96 is internally splined as at 138 to provide a splined connection with the upper end of a relatively small diameter torsion shaft 140. Likewise, the upper end of tubular shaft 122 is internally splined as at 142 to provide a splined connection with the upper end of a second torsion shaft 144. The lower enlarged end portion 146 of torsion shaft hasa close fit within the lower end of tubular shaft 96 and the lower enlarged end portion 148 of torsion shaft 144 has a close fit with the lower end of tubular shaft 122. A bevel gear 150 is fixedly secured to the lower end of torsion shaft 140 and a similar bevel gear 152 is fixedly secured to the lower end of torsion shaft 144. Bevel gear 150 meshes with a bevel gear 154 and bevel gear 152 likewise meshes with a bevel gear 156. Bevel gears 154 and 156 are mounted on a splined sleeve I58 and are retained in fixed spaced apart relation on sleeve 158 by a spacer 160. Sleeve 158 in turn is fixed to propeller shaft 116 by a pin 162.

With the above-described drive arrangement it will be observed that shafts 68 and 96 are interconnected at a fixed driving angle by universal joint 80. In the arrangement illustrated the axis of shaft 68 intersects the axis of shaft 96 at an angle of 30and, as pointed out previously, the axes of torsion shafts I40, 144 intersect the axis of propeller shaft 116 at an angle of approximately 60.

The above-described drive arrangement possesses certain distinct advantages over the conventional inboard outboard drive. The universal joint 80 replaces a set of bevel gears normally used in the previously described conventional inboard outboard drive. As a consequence, friction losses and noise inherent in such gears are eliminated. In addition, the cost of universal joint 80 is substantially less than the cost of the otherwise required set of bevel gears. This is true even though universal joint 80 and universal joint 64 are of the uniform angular velocity type.

Another advantage of the drive arrangement described above is the minimum drag presented by the underwater por tion of the drive casing; that is, the portion below anticavitation plate 112. With the present arrangement the submerged portion of the casing enclosing the drive unit is of a minimum size for several reasons. In the first place shaft 96 is inclined to the axis of propeller shaft 116 at an acute angle. This being the case it necessarily follows that the bevel gears 150, 152, 154, 156 can be of smaller diameter as compared to an arrangement wherein the driven shaft is perpendicular to the propeller shaft. Furthermore, the drive from shaft 96 is divided between shafts 140 and 144. The division of the drive in this manner also reduces the size of the driving bevel gears. Furthermore, it will be appreciated that since shafts 140, 144 are inclined to the axis of propeller shaft 116 at an acute angle the pitch diameter of the bevel gears connecting these shafts is substantially reduced because the ratio between the major and minor pitch ofthe driven bevel hears is likewise reduced. Thus the elimination of the conventionally used upper set of bevel gears results in a stronger construction of the lower set of bevel gears and makes possible a substantially stronger construction of the stern drive as compared with conventional types of similar drives. The lower drag presented by the stern drive of this invention allows a higher boat speed at the same outboard or, stated differently, lower power requirement for equal speed as compared with conventionally constructed stern drives.

it will also be observed that, while shaft 96 is a tubular shaft of relatively large diameter and is therefore relatively rigid, shafts 140 and 144 are solid shafts of relatively small diameter. Thus, while shafts 140, 144 are of sufficient size and strength to transmit the required torque to propeller shaft 116, they serve as torsion shafts and thus absorb instantaneous angular variations in torque between the two shafts so as to equalize the torque transmitted to the propeller shaft. Shafts 140, 144, which are of equal length, are capable of operating as torsion shafts not only because of their size but also because of their splined connections with tubular shafts 96 and 122, respectively, which enable the splined ends of the shafts to shift axially slightly, if necessary, to accommodate the torsional deflection in each of the shafts.

Referring again to FIG. 1, there is illustrated at 164 a steering arm which is pivotally connected to a steering link 166 as at 168. The pivotal connection 168 includes a ball joint which permits universal pivoting movement oflink 166. The free end of link 1656 is connected to a fixed bracket 170 in casing 50 by a ball joint 172 arranged for axial sliding movement in a cyiindrical socket 174. Link 166 is bent around the illustrated drive shafts and its sliding ball joint connection with casing 50 enables the link to pivot universally about pivot point 168 even though this latter pivot point is offset slightly from the pivot axis of universal joint 64.

Referring to FIGS. 1 and 2, a pair of axially extensible hydraulic shock absorbers 176, 178 extend generally horizontally within the upper casing part 104 and are pivotally connected thereto at their outer ends as at 180. The inner or forward ends of shock absorbers 176 are pivotally connected by pins 182 to one of a plurality of apertures 184 formed on depending lugs 186 at the lower end of bracket 40 which straddle opposite sides of casing 50. A plurality of apertures 184 are provided to enable adjustment of the tilt angle of the drive unit as a whole relative to the transom of the boat. Shock absorbers 176 are designed to permit the entire casing 50 and the drive unit contained therein to pivot upwardly and rear wardly in the event it strikes an underwater obstruction and to permit the drive unit to be tilted upwardly out of the water for servicing.

Shock absorbers 176, 178 are preferably also formed as hydraulic power cylinders. One end of each cylinder is connected by a conduit 188 to one port 189 of an oil pump 190 and the opposite ends of each cylinder are connected by flexible conduits 192 with another port 193 of oil pump 190. Although controls for pump 190 are illustrated, it will be appreciated that suitable controls are provided for directing fluid under pressure from port 193 to the inner or forward ends of cylinders 176, 178 to tilt the drive unit upwardly and for directing fluid under pressure from port 189 through conduit 192 to the rear or outer ends of cylinders 176, 178 for tilting the driving unit downwardly. The lowermost tilted position of the drive unit is, of course, determined by the set of apertures 184 to which the inner ends of cylinders 176, 178 are connected.

Although a reverse mechanism for the drive unit is not illustrated, it will be appreciated that such mechanism can be provided at any suitable location; for example, it can be located between the engine and drive shaft 56. On the other hand, it can be located within the drive casing 50 ifdesired,

It will be observed that all of the driving and related parts of the inboard outboard drive arrangement shown and described herein are contained substantially within casing 50. Thus, the controls and driving parts are protected from corrosion and are also protected from damage which might be caused by heavy seas or collision.

lclaim:

1. An inboard outboard drive for a boat having an inboard engine with a drive shaft extending rearwardly through a transom of the boat which comprises a casing adapted to be mounted on the transom of the boat for universal pivoting movement; a first universal joint within said casing to which said drive shaft is adapted to be connected; a first driven shaft journaled in said casing about a fixed axis and connected at one end of said universal joint; a second driven shaft journaled in said casing about a fixed axis which is inclined downwardly and rearwardly at an acute angle to the horizontal when the casing is in a normal drive position; a second universal joint connected to the upper end of said inclined shaft and with the other end of said first driven shaft; a propeller shaft journaled in said casing for rotation about a fixed axis inclined to the axis of the second driven shaft at an acute angle and extending generally horizontally when the casing is in said normal drive position and means including bevel gearing interconnecting the lower end of said inclined shaft and said propeller shaft.

2, An inboard outboard drive as called for in claim 1 wherein said last-mentioned means comprises a pair of shafts parallel to said inclined shaft, means forming a drive connection between said driving shaft and said pair of shafts, said bevel gearing comprising a bevel gear at the lower end of each of said parallel shafts and a pair of bevel gears spaced axially along the propeller shaft and meshing with said first-mentioned bevel gears.

3. An inboard outboard drive as called for in claim 2 wherein said pair of parallel shafts comprises relatively small diameter torsion shafts having one end supported for slight axial movement in response to relative torsional deflection between opposite ends of the shafts.

4. An inboard outboard drive as called for in claim 2 wherein said pair of parallel shafts are inclined to the axis of the propeller shaft at an angle of about 60.

5. An inboard outboard drive as called for in claim 2 wherein said means connecting the inclined shaft and said pair of parallel shafts comprises a plurality of spur gears.

6. An inboard outboard drive as called for in claim 2 wherein said means connecting the inclined shaft and said pair of parallel shafts includes a pair of spur gears, one on each of said shafts, and an intermediate spur gear meshing with said pair of spur gears for driving said pair of shafts in the same direction.

7. An inboard outboard drive as called for in claim 2 wherein each of said parallel shafts includes a tubular shaft journaled at opposite ends in said casing and an inner shaft within each tubular shaft, said first-mentioned bevel gears being fixed to the lower ends of said inner shafts, said inner shafts having a splined connection with said tubular shafts at their upper ends.

8. An inboard outboard drive as called for in claim 1 wherein said first driven shaft is journaled in said casing with its axis extending in a downwardly and rearwardly inclined direction.

9. An inboard outboard drive as called for in claim 1 wherein the axes of the inclined shaft and the propeller shaft intersect at an inclined angle of about 60.

[0. An inboard outboard drive as called for in claim 9 wherein said first driven shaft inclines downwardly and rearwardly from said first universal joint at an angle of about 30 from the horizontal.

11. An inboard outboard drive as called for in claim 1 wherein said inclined shaft is of tubular shape adjacent its lower end and including an internal shaft disposed within the tubular portion of the inclined shaft, said internal shaft projecting axially beyond the lower end of the tubular shaft, said bevel gearing comprising a bevel gear on the projecting end of said internal shaft meshing with a bevel gear on the propeller shaft, the upper end of the internal shafl having an axially splined connection with said inclined shaft and the lower end of said internal shaft being capable of torsionally flexing relative to the upper end of the internal shaft and relative to the tubular shaft.

12. In an inboard outboard drive for a boat the combination comprising, a support bracket adapted to be fixedly mounted on the transom of the boat; a steering bracket journaled on said support bracket for pivotal movement about a generally vertical axis; a casing journaled on said steering bracket for pivotal movement about a generally horizontal axis; a drive unit in said casing including a propeller shaft; means for connecting said drive unit with the drive shaft of the inboard engine; and extensible shock-absorbing hydraulic cylinder means connected at one end with said casing and at the other end with said steering bracket.

13. The combination set forth in claim 12 wherein said shock-absorbing cylinder means comprises at least one double-acting hydraulic cylinder and including a fluid pressure supply source optionally connectable with opposite ends of said hydraulic cylinder for tilting said casing upwardly and downwardly about said horizontal axis. 

1. An inboard outboard drive for a boat having an inboard engine with a drive shaft extending rearwardly tHrough a transom of the boat which comprises a casing adapted to be mounted on the transom of the boat for universal pivoting movement; a first universal joint within said casing to which said drive shaft is adapted to be connected; a first driven shaft journaled in said casing about a fixed axis and connected at one end of said universal joint; a second driven shaft journaled in said casing about a fixed axis which is inclined downwardly and rearwardly at an acute angle to the horizontal when the casing is in a normal drive position; a second universal joint connected to the upper end of said inclined shaft and with the other end of said first driven shaft; a propeller shaft journaled in said casing for rotation about a fixed axis inclined to the axis of the second driven shaft at an acute angle and extending generally horizontally when the casing is in said normal drive position and means including bevel gearing interconnecting the lower end of said inclined shaft and said propeller shaft. CM,2Nboard outboard drive as called for in claim 1 wherein said last-mentioned means comprises a pair of shafts parallel to said inclined shaft, means forming a drive connection between said driving shaft and said pair of shafts, said bevel gearing comprising a bevel gear at the lower end of each of said parallel shafts and a pair of bevel gears spaced axially along the propeller shaft and meshing with said first-mentioned bevel gears.
 3. An inboard outboard drive as called for in claim 2 wherein said pair of parallel shafts comprises relatively small diameter torsion shafts having one end supported for slight axial movement in response to relative torsional deflection between opposite ends of the shafts.
 4. An inboard outboard drive as called for in claim 2 wherein said pair of parallel shafts are inclined to the axis of the propeller shaft at an angle of about 60*.
 5. An inboard outboard drive as called for in claim 2 wherein said means connecting the inclined shaft and said pair of parallel shafts comprises a plurality of spur gears.
 6. An inboard outboard drive as called for in claim 2 wherein said means connecting the inclined shaft and said pair of parallel shafts includes a pair of spur gears, one on each of said shafts, and an intermediate spur gear meshing with said pair of spur gears for driving said pair of shafts in the same direction.
 7. An inboard outboard drive as called for in claim 2 wherein each of said parallel shafts includes a tubular shaft journaled at opposite ends in said casing and an inner shaft within each tubular shaft, said first-mentioned bevel gears being fixed to the lower ends of said inner shafts, said inner shafts having a splined connection with said tubular shafts at their upper ends.
 8. An inboard outboard drive as called for in claim 1 wherein said first driven shaft is journaled in said casing with its axis extending in a downwardly and rearwardly inclined direction.
 9. An inboard outboard drive as called for in claim 1 wherein the axes of the inclined shaft and the propeller shaft intersect at an inclined angle of about 60*.
 10. An inboard outboard drive as called for in claim 9 wherein said first driven shaft inclines downwardly and rearwardly from said first universal joint at an angle of about 30* from the horizontal.
 11. An inboard outboard drive as called for in claim 1 wherein said inclined shaft is of tubular shape adjacent its lower end and including an internal shaft disposed within the tubular portion of the inclined shaft, said internal shaft projecting axially beyond the lower end of the tubular shaft, said bevel gearing comprising a bevel gear on the projecting end of said internal shaft meshing with a bevel gear on the propeller shaft, the upper end of the internal shaft having an axially splined connection with said inclined shaft and the lower end of said internal shaft being capable of torsionally flexing relative to the upper end of the internal shaft and relatiVe to the tubular shaft.
 12. In an inboard outboard drive for a boat the combination comprising, a support bracket adapted to be fixedly mounted on the transom of the boat; a steering bracket journaled on said support bracket for pivotal movement about a generally vertical axis; a casing journaled on said steering bracket for pivotal movement about a generally horizontal axis; a drive unit in said casing including a propeller shaft; means for connecting said drive unit with the drive shaft of the inboard engine; and extensible shock-absorbing hydraulic cylinder means connected at one end with said casing and at the other end with said steering bracket.
 13. The combination set forth in claim 12 wherein said shock-absorbing cylinder means comprises at least one double-acting hydraulic cylinder and including a fluid pressure supply source optionally connectable with opposite ends of said hydraulic cylinder for tilting said casing upwardly and downwardly about said horizontal axis. 